Review: Holden VZ One Tonner (2004-05)

Overview

Released in August 2004, the Holden VZ One Tonner was a two-door cab chassis. Manufactured in Elizabeth, South Australia, the VZ One Tonner was available with newly-introduced 3.6-litre V6 and 5.7-litre V8 petrol engines. As per the table below, the VZ One Tonner range initially consisted of rear-wheel drive One Tonner and One Tonner S models. In March 2005, however, four-wheel drive Cross 6 variants were released.

Engines: Alloytec V6 and LS1 V8

Of the engines,

• The newly-introduced 3.6-litre ‘Alloytec’ LE0 V6 petrol engine had all-aluminium construction, a forged steel crankshaft, forged powdered metal connecting rods, twin knock control sensors, double overhead camshafts (DOHC), sequential electronic fuel injection, four valves per cylinder, continuously variable intake camshaft phasing, electronic throttle control, a compression ratio of 10.2:1 and coil-on-plug ignition. Impressively, ninety per cent of peak torque was available from 1630-5460 rpm; and,
• The 5.7-litre LS1 pushrod V8 engine had all-aluminium construction, flat-topped pistons, two valves per cylinder, twin knock control sensors and a compression ratio of 10.1:1. For the VZ range, the LS1 engine received electronic throttle control.

Transmissions

Of the rear-wheel drive V6 models, the One Tonner was available with four-speed 4L65E automatic and six-speed Aisin D173/AY6 manual transmissions; the Cross 6, however, was solely available with the four-speed 4L60E transmission. Models with V8 engines were fitted either 4L65E automatic or six-speed Tremec T56 manual transmissions.

Development and VY comparison

In addition to the 3.6-litre Alloytec V6 engine, the VZ One Tonner introduced improved off-centre steering feel, Bosch 8.0 ABS (for models with V6 engines) and new brake boosters, brake master cylinders and power steering pumps. Visually, the VZ One Tonner could be identified by its new grille, bonnet and more compact headlights.

Like the VY One Tonner , the VZ One Tonner had part-monocoque and part chassis frame construction with a ‘torque arm’ system which consisted of two vertical uprights at the front of the chassis frame which bolted to the back of the cab. Similarly, the VZ One Tonner was 5230 mm long, 2047 mm wide, 1507 mm tall and had a 3200 mm long wheelbase.

Suspension

The VZ One Tonner had MacPherson strut front suspension and a live rear axle with leaf springs, a reinforced prop shaft and rear axle housing, heavy duty wheels and specially developed tyres. As a result, the One Tonner had maximum front and rear axle loads of 1180 kg and 1800 kg, respectively. Gross Vehicle Mass was 2826 kg and, allowing for fuel, passengers, a rear tray and other accessories, payload was greater than 1000 kg for typical work situations.

For the VZ One Tonner, changes were made to front stabiliser bar geometry for sharper steering response.

Cross Trac: permanent four-wheel drive system

The Cross 6 variants were fitted with Holden’s ‘Cross Trac’ permanent four-wheel drive system which included a New Venture NV124GM transfer case and three open differentials (front, centre and rear). In normal conditions, the Cross Trac system provided a 38:62 front:rear torque split.

In the event that excessive wheel spin was detected at any wheel, the brakes would be applied to that wheel to redistribute torque to the wheels with more traction – this operation was termed an ‘automatic brake differential’ or ABD by Holden. Developed by Holden for local conditions, the Cross Trac system included calibrations for dirt roads and loose surfaces.

Safety equipment

Standard safety equipment for the VZ One Tonner included a driver’s airbag and front seatbelts with pretensioners and load limiters.

The One Tonner S was further equipped with ABS, while One Tonner S models with V6 engines were also equipped with brake assist electronic brake force distribution. Relative to the V6-powered One Tonner S, the Cross 6 added traction control.

Brakes

The VZ One Tonner had 296 mm by 28 mm vented front brake discs with twin-piston calipers and 286 mm by 16 mm solid rear brake discs with single piston calipers.

Features

Standard features for the VZ One Tonner included 15-inch steel wheels, a four speaker sound system with CD player, cruise control, automatic head lights, remote central locking, power adjustable driver’s seat, power windows and mirrors, height and reach adjustable steering column, trip computer and immobiliser; the Cross 6 was similarly equipped but had 16-inch steel wheels.

The One Tonner S was further equipped with 16-inch alloy wheels, air conditioning and a leather-wrapped steering wheel.

Specifications

• Specifications: Alloytec V6 engine (July 2004)
• Specifications: VZ Ute, Crewman and One Tonner (August 2004)
• Specifications: Holden VZ Ute, Crewman and One Tonner (May 2005)
• Specifications: Holden VZ One Tonner and Crewman – Cross 6 and Cross 8 (May 2005)

Related links

• Product Information: VZ Ute, Crewman and One Tonner (August 2004)
• Holden Media Archive: Holden’s New All Wheel Drive One Tonner Cross 6 (February 2005)
• Wikipedia.org: Holden VZ Ute, One Tonner and Crewman